Duplex boiler and furnace wall having water walls



D. H. N. MAYO Aug 15, 1933.

DUPLEX BOILER AND FURNACE WALL HAVING WATER WALLS Filed Oct. 16, 1930 5 Sheets-Sheet 1 INVENTOR BY Wjwdfiv I ATTORNEY:

D. H. N. MAYO 1,922,665

DUPLEX BOILER AND FURNACE WALL HAVING WATER WALLS Aug. 15, 1933.

Filed Oct. 16, 1930 3 Sheets-Sheet 2 3M KI7IZI'VENTOR BY WJMO 4 ATTORNEYS Patented Aug. 15, 1933 UNITED STATES PATENT OFFICE DUPLEX BOILER AND FURNACE WALL HAVING WATER WALLS poration of Delaware Application October 16, 1930. Serial No. 489,067

2 Claims.

This invention relates to a boiler construction that is provided with two separate boilers and a single furnace with water-cooled walls in which rows of tubes are connected separately to the respective boilers.

The invention will be understood from the description in connection with the accompanying drawings in which l is a vertical section through an illustrative embodiment of the invention; Fig. 2 is a vertical section along the line 22 of Fig. 1 and Fig. 3 is a horizontal section along the line 3-3 of Fig. 2.

In the drawings reference character 1 indicates the furnace above which two water tube boilers are located, the respective boilers having a steam and water drum along opposite sides of the boiler setting in this parti ular embodiment of the invention. The boilers as shown have steam and water drums 2 and 2, respectively. Each drum is connected to the downtake headers 3 and uptake headers 4 of its boiler by means of nipples 5 and circulation tubes 6, res ectively. The headers 3 and 4 are connected by banks of inclined tubes 7 across which the hot gases from the furnace pass. The lower portions of the uptake headers 4 are connected by rows of inclined tubes 8 to mud drums 9 that are connected by means of nipples to the headers 3. The "tubes 8 are spaced apart farther than the tubes '7, as indicated in Figs. 1 and2 to form slag screens for the boilers.

A closure 10 is provided at the lower end of the space between the headers 4 so that the gases from the furnace will be forced to pass across the tubes 8, 'land 6 to the staclt (not shown).

The furnace 1 is provided with fuel burners 10 along opposite walls and these walls are provided with upwardly extending tubes 11 and 11', respectively. The lower ends of the tubes 11 and 11' are connected to horizontally disposed lower headers 12 and 12 and their upper ends extend outwardly from the furnace walls and are connected to upper horizontally disposed headers 13 and 13. Return circulation tubes 14 and 14 extend from the headers 13 and 13 to horizontal headers 15 and 15' parallel to the headers 12 and 12" and outside of the furnace walls. Tubes 16 and 16 connect the headers 15 and 15" to the headers 12 and 12'.

the furnace walls into upper horizontally disheaders 19 and 19. Return circulation tubes 20 and 2G connect the ends of the headl9 and 19 to the ends of the headers 18 and 18' and rows of return circulation tubes a1 and 21 of smaller size connect the headers 18 and The headers 12, 12, 13,13, 18, 18', 19, and 19 are divided into two sections at therniddle thereof, either by making these headers in two sepsections, or by means of a partition at the middle of longer headers and these headers are connected to the boiler circulation systems of the two boilers in such a way that the tubes along one half of the furnace are connected sole- 1y to one boiler and the tubes along the other half of the furnace are connected only to the other boiler.

Groups of nipples 25 and 25 connect the water spaces of the steam and water drums 2 to headers 26 and 26 from which downtake tubes 27 and 2'7 lead to vertically disposed headers 28 and 28'. Tubes 29 and 29' lead from the headers 28 and 28' to the headers 12 and 12 and tubes 30 and 30 lead from the headers 28 and 28 to the headers 18 and 18. Tubes 31 and 31' extend from the headers 13 and 13 to steam spaces of the steam and water drums 2 and tubes 32 and 32' Xtend from the headers 19 and 19 to the steam spaces of these drums. A slag tap opening 33 is provided through one of the furnace walls a short distance above the furnace floor 34 that is made of refractory material supported upon the supports 35. The molten slag from the products of combustion collects upon the floor of thefurnace, as indicated at 36, and may be tapped out through the opening 33 at intervals. 1

The circulation from one of the boilers through the water wall tubes of half of the furnace and back the same as that from the other boiler through the other half of the furnace Wall tubes. Water passes from the water space of the steam and water drum 2 through the sets of nipples 25 near each end of one of the drums 2 into the headers 26, thence through the downtake tubes 27 to the headers 28 near the corners of the furnace, thence through the tubes 29 and 30 to one half of the lower headers 12, 12' and the lower header 18, thence upwardly through one half of the wall tubes 11, 11 and wall tubes 17 into one half of the headers 13, 13 and the header l9, thence through tubes 31 and 32 to the steam space of the steam and water. drum 2.

The circulation through the other half L of the furnace is in the same way from the other steam and water drum 2 through similar connections. In this way there are two independent circulation systems through the furnace wall tubes.

The water tubes of a furnace wall in which one set of burners is located and the water tubes of the side wall sections immediately adjacent thereto are connected to a boilerabove them and the other furnace wall tubes are connected to the other boiler which is above them. There is no inter-connection between the two boilers or the furnace wall tubes in the two halves of the furnace, so that the danger of troubles arising due to one half of the furnace being heated hotter than the other at times is eliminated. The circulation in each half of the furnace depends upon the rate of heating in that half. Also, since the two boiler systems are kept separate Without any inter-connection between them, no surges back and forth from one boiler to another is possible when rate of steaming and water levels vary in the wo boilers. Rate of steaming and water levels in boilers connected to the two halves of the furnace difier when the fuel burning means are so arranged or operated that considerably more heat is generated in one portion of the furnace than in another.

With this invention unequal feed or circulation of water from the boilers through the wa-.

ter walls can be obviated; troubles due to unequal heat development in different parts of the furnace, as for example by using burners on one side only, do not arise; and the heat in the furnace is satisfactorily absorbed even with unequal fuel flow into different parts or unequal drafts through the two boilers. Although the two boilers are shown set end to end, they may be set side by side, and more than two boilers may be used, each connected to a portion of the furnace wall tubes independently of the others.

I claim:

1. In combination, a furnace, water tube boilers above said furnace, and upwardly disposed tubes in the walls of said furnace, upper and lower headers to which tubes in opposed walls are connected and the tubes in one half of said furnace walls being connected to the water circulation system of one of said boilers only and the tubes in the other half of said furnace being connected to the water circulation system of the other boiler only.

2. In combination, a furnace, water tube boilers above said furnace, and upwardly disposed tubes in the Walls of said furnace, upper and lower headers to which tubes in opposed walls are connected, said headers being divided near the middle thereof, and the tubes in one half of said furnace walls being connected to the water circulation system of one of said boilers only and the tubes in the other half of said furnace walls being connected to the water circulation system of the other boiler only.

DANA H. N. MAYO. 

